A conventional backlight device, such as one disclosed in International Patent Application Publication No. WO 2011/125356 A, includes a light guide plate with first and second side surfaces opposed to each other. A first illuminant is positioned closest to the first side surface, and a second illuminant is positioned closest to the second side surface.
Light emitted from the first illuminant and light emitted from the second illuminant are not mixed on respective sides of the first and second side surfaces of the light guide plate, forming a region irradiated with only a single light from each illuminant. While a mixed colored light, which is a mix of light emitted from the first illuminant and light emitted from the second illuminant, is emitted from the central part of the light guide plate, a light having a different color than the mixed colored light is emitted from the side of the first side surface.
Likewise, a light emitted from the side of the second side surface of the light guide plate is a different color than the mixed colored light emitted from the central part of the light guide plate.
Thus, in the conventional backlight device, color unevenness occurs on the respective sides of the first and second side surfaces at the emission surface of the light guide plate.